Next day I noticed it back on the original desk. So I moved it to another spot... actually it was one of those "Hiding in plain sight" places... atop a display at the front of the office.
Next time I was there... it's back and I move it again...
This has continued through the last few weeks, including the night time, weekend stuff.
Today, the guy I'm working with asks me before I leave...
"Hey... wait... did you do the golf ball thing?"
"hmmmm" (I demure...)
"No really... make sure you did whatever you do in there... the ladies in the office have this huge deal going on first thing in the morning after you've been here... they all go nutty hunting around for the golf ball... and... no no really, they get all excited about finding it... They know it's you and they keep asking me when the next time you're coming to the office..."
"Yo" (I say) "took care of that the minute I got here... "
:D